As a related art, there is known, for instance, by Patent Document 1, a control device having, in addition to a normal shift mode that continuously varies a transmission ratio, a shift mode (hereinafter called a pseudo stepwise up-shift mode) that controls the transmission ratio so as to increase a vehicle speed while repeating gradual increase and rapid decrease of an engine rotation speed by varying the transmission ratio stepwise, like a stepwise variable transmission (or a multi-range transmission).
Further, there is a vehicle having a travelling mode called a sports mode that can realize a sportier run than a normal drive mode. The sports mode is a mode in which the engine rotation speed and the transmission ratio are controlled so as to be high as compared with the drive mode. The sports mode is superior to the drive mode in acceleration performance and engine brake. In a case where a driver selects such sports mode, by the fact that the continuously variable transmission is controlled to the pseudo stepwise up-shift mode, the driver can feel the stepwise up-shift during acceleration, then it is possible to produce sportier feeling.
In recent years, an attempt to produce the up-shift feeling during the acceleration by providing the pseudo stepwise up-shift mode to a plurality of drive modes has been made. For instance, the pseudo stepwise up-shift mode is provided to the drive mode, and also the pseudo stepwise up-shift mode is provided to the sports mode. In this case, by setting a shift speed during the up-shift in the pseudo stepwise up-shift mode of the sports mode to be higher than a shift speed during the up-shift in the pseudo stepwise up-shift mode of the drive mode, it is possible to obtain even sportier drive feeling.
In a control of the pseudo stepwise up-shift mode, since an inertia torque is generated by the up-shift, an engine torque control is carried out so as to cancel this inertia torque. That is, by reducing the engine torque by an amount of the inertia torque generated during the up-shift, variation of an output torque is prevented, and a shift shock upon the up-shift can be suppressed.
However, in the case where the shift speed during the up-shift in the pseudo stepwise up-shift mode is set to be different between the drive mode and the sports mode, it is also required that different torque control be performed between the drive mode and the sports mode in order to suppress the shift shock. For instance, in the case where, as described above, the shift speed during the up-shift in the pseudo stepwise up-shift mode of the sports mode is set to be higher than that of the drive mode, it is necessary to absorb the inertia torque generated during the up-shift for a short shift time.
Because of this, in the sports mode, a torque reduction amount at a start of the up-shift is greater than that of the drive mode, then the shift shock tends to be great. In other words, in the sports mode, a response of the shift is more important than the shift shock. In the drive mode, lowering the shift shock is more important than the response of the shift.
However, in a case where the driver changes the travelling mode during the progress of the up-shift in the pseudo stepwise up-shift mode, since the shift speed during the up-shift is changed halfway through the up-shift, harmonization between the pseudo stepwise up-shift control and the engine torque control cannot be made, and this causes a problem of generating the shift shock.